Altersbestimmung an thermalen Tiefenwässern im Oberjura des Molassebeckens mittels Krypton-Isotopen

Journal Article · Wed Sep 25 00:00:00 EDT 2019 · Grundwasser

DOI:https://doi.org/10.1007/s00767-019-00431-0· OSTI ID:1580732

Heidinger, Michael ^[1]; Eichinger, Florian ^[1]; Purtschert, Roland ^[2]; Mueller, Peter ^[3]; Zappala, Jake ^[3]; Wirsing, Gunther ^[4]; Geyer, Tobias ^[4]; Fritzer, Thomas ^[5]; Groß, Doris ^[6]

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1. Hydroisotop GmbH, Schweitenkirchen (Deutschland)
2. Univ. of Bern, Bern (Schweiz)
3. Argonne National Lab. (ANL), Lemont, IL (United States)
4. Abt. 9 – Landesamt f. Geologie (Deutschland)
5. Bayerisches Landesamt für Umwelt, Augsburg (Deutschland)
6. Montanuniversität, Leoben (Osterreich)

⁸¹Kr (half-life 229,000 years) is an ideal tracer for old groundwater. The Upper Jurassic rock in the deep Molasse Basin is an outstanding geothermal groundwater reservoir (with temperatures up to 140 °C). However, due to the complex groundwater evolution (ion and isotope exchange, gas flux, etc.), comprehensive hydrogeological studies completed to date, including ¹⁴C–DIC and He isotopes, could not resolve the recharge dynamics and residence times. Nine geothermal wells were therefore sampled for ⁸¹Kr/⁸⁵Kr employing the laser-based atom trap tracer analysis technique (ATTA). In the western and central basin, the results reveal predominant groundwater recharge during the last glacial period with one sample influenced by infiltration during the earlier glacial period. Recharge signatures and ⁸¹Kr-model-ages fit very well to subglacial recharge with cross-formational flow through the sedimentary cover (600 to >3000 m deep). In the eastern basin, the results point to the Cromerian complex, indicating a slower flow system with less influence from recharge during glacial periods.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: Hydroisotop GmbH
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1580732
• Alternate ID(s): OSTI ID: 23014063
• Journal Information: Grundwasser, Journal Name: Grundwasser Journal Issue: 4 Vol. 24; ISSN 1430-483X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
81Kr
85Kr
ATTA
Molasse basin
cross-formational flow
dating
isotope
krypton
old groundwater
recharge